Bidding : 1D (N) - 1S (E) - DBL (S) - 3H (N) - 4H (S)

Opening Lead : King of Spades (E) = top of a solid sequence

Declarer (N) counts 5 possible losers : one in Spades, one in hearts if the trumps break badly, two in Diamonds and one in Clubs.

Declarer Play
Negative Double   -   Ruffing before drawing trumps   -   Double finesse
East wins the opening lead with the Spade King, then leads his Spade Queen which is ruffed by Declarer. At trick 3 Declarer leads a small Club to Dummy's Ace, who then leads his last small Spade for a second ruff by Declarer.

At trick 5 Declarer leads the trump Ace, followed by his last trump to Dummy's King.
At trick 7 Dummy leads the Diamond 9 for a double finesse (against A and J). West and Declarer both play low and East wins with the Ace. East leads his Spade Jack, ruffed by Dummy, who now draws the last enemy trump with his 10 (Declarer discarding a small Club), and (at trick 9) leads his last small Diamond. West plays low and Declarer wins with the 10. The remaining tricks are won by Declarer's K and Q of Diamonds and the K of Clubs, a total of 11 tricks.

Score = 5 x 30 trick pts + 300 bonus pts = 450 pts total

Bidding : 1C (E) - 1H (S) - DBL (W) - 2S (E) - 4S (W)

Opening Lead : King of Hearts (S) = top of an interrupted sequence

Declarer (E) counts 4 possible losers : one in Spades, two in Hearts, one in Diamonds and one in Clubs if the enemy Clubs don't break 3-3. He can ruff one Heart and one Club in Dummy if required.

Declarer Play
Negative Double   -   Bath Coup   -   Avoidance play
North Discourages with the Heart 3 on the opening lead and Declarer holds up and plays low (Bath Coup). South then switches to a small Club, North plays the 10 and Declarer wins with the Ace.
At trick 3 Declarer leads a small trump to Dummy's Ace, who in turn leads a small trump. When North plays low Declarer finesses with the 10, determined to keep North of the lead for now (so that he can not play through Declarer's A J of Hearts) and wins.

At trick 5 Declarer plays his trump King, drawing North's Queen, then plays two more rounds of Clubs ending in his hand. The Clubs break 3-3 and on Declarer's 4th Club winner (trick 8) Dummy discards a Diamond.
Things are looking very good now and Declarer boldly leads a low Diamond to Dummy's Queen which wins. Dummy then (trick 10) leads the Diamond Ace, followed by a small Heart to Declarer's Ace. Declarer's remaining Jack of hearts is ruffed in Dummy, leaving Declarer with a trump for the last trick.
Some days everything just works out great. Total tricks made : 12.

Score = 6 x 30 trick pts + 500 bonus pts = 680 pts total

Bidding : 1H (S) - 1S (W) - DBL (N) - 1NT (S) - Pass (N)
North can bid 2C at his 2nd turn if he wishes (instead of Pass), showing 5 Clubs and 6-10 points. South should Pass on that.

Opening Lead : 7 of Spades (W) = 4th card from the top

Declarer (S) counts 5 sure winners : four Aces plus the King of Hearts. The opening lead ensures a 6th sure winner in Spades.
Additional tricks can come from Hearts if they split 3-3 or from Clubs. Clubs being the better option.

Declarer Play
Negative Double   -   Free finesse   -   Double finesse
Dummy plays low and Declarer wins the opening lead with the Jack. He then plays his Club 9 for a direct double finesse. West plays low and East wins with the King.
At trick 3 East leads another Spade. Declarer ducks (holding up his Ace) and West wins with the Queen. A third Spade from West is won by Declarer's Ace (East is now out of Spades to lead to his Partner's winners). At trick 5 Declarer leads his remaining small Club to Dummy's Jack which wins the trick. Dummy then plays the Club Ace, which drops the Queen, followed by two more Club winners. Declarer then cashes his remaining winners A K of Hearts and the A of Diamonds, making 9 trick total.
(If he tries to develop the Hearts West will gain the lead and cash his two Spade winners holding Declarer to 8 tricks only.)

Score = 40 + 2 x 30 trick pts + 50 bonus pts = 150 pts total

Bidding : Pass (W) - Pass (N) - 1D (E) - 1H (S) - 1S (W) - 3S (E) - 4S (W)
By bidding 1S instead of a Double West shows a 5 card suit, which East jump raises (now having 16 pts). West with 11 pts accepts the invitation and bids Game.

Opening Lead : Queen of Hearts (N) = top of touching Honours of Partner's suit

Declarer (W) counts 4 possible losers : A K of Hearts, the A of Clubs, plus a trump loser if the enemy Spades split 4-1. But if the Spade Jack (or 10) falls on the first trump trick he can finesse the 10 (or Jack).

Declarer Play
Responder showing a 5 card suit   -   Safety play
North wins the first trick and continues with the heart Jack which wins the second trick. Seeing Dummy is now void in Hearts he switches to a small Club, won by Partner's Ace. At trick 4 South leads a small Diamond, won by Declarer with the Ace.
Declarer now leads his trump King. This is a safety play, for if either the 10 or Jack falls on this first Spade trick Declarer can finesse the other card of this duo in either direction. He holds Q and 9 in his own hand and A and 8 in Dummy. If instead he had played Dummy's trump Ace on the first trick he could only have finessed on the second trick in one direction.
The enemy trumps break 3-2 however and the finesse option is not required. Declarer wins all remaining tricks without any problem, making 10 tricks in total.

Score = 4x 30 trick pts + 300 bonus pts = 420 pts total